Conventionally, for window glass of vehicles such as automobiles, glass articles are used such as anti-fogging glass provided with anti-fogging hot wires, and glass antennas for receiving ratio waves from the outside of vehicles. Of these glass articles, for example, anti-fogging glass typically has a conductive film formed in a predetermined pattern by applying a conductive paste in the form of lines onto a glass substrate, and then the paste is fired. Various types of paste have been developed and proposed for this purpose.
For example, Patent Document 1 proposes a conductive paste for producing conductive coatings on glass, ceramics, or porcelain enamel steel. The conductive paste includes conductive silver particles, conductive particles containing at least one base metal, one or more types of glass frit, and a paste formation medium. The base metal-containing conductive particles are substantially composed of iron, cobalt, nickel, copper, zinc, or an alloy including at least one of the elements. The average particle size D50 of the base metal-containing conductive particles falls within the range of 0.1 μm to 15 μm, the specific surface area thereof falls within the range of 0.5 m2/g to 10 m2/g, and the base metal-containing conductive particles account for up to 80 weight % of the whole conductive particles. The softening temperature (by heating microscope) of the one or more types of glass frit falls within the range of 350° C. to 600° C., and the hemisphere temperature thereof falls within the range of 450° C. to 700° C.
This Patent Document 1 is intended to achieve a conductive paste which has a stable resistivity of approximately 37 to 40 μΩ·cm even when the firing temperature varies in the range of 660 to 680° C.
Patent Document 1: Japanese Patent No. 3960921 (claim 1; paragraphs [0009], [0019] to [0021], Table 2, etc.)